La Réunion , Piton de la Fournaise :

The eruption started on September 15th at 4:25 am local time continues. The intensity of the volcanic tremor (indicator of eruptive intensity at the surface) has stabilized for about 24 hours, at a very low level (Figure 1).

– No volcano-tectonic earthquake was recorded during the day of 24 October or during the current day.
– Inflation (swelling) of the building is always recorded. This inflation reflects the pressurization of a localized source beneath the summit craters (Bory-Dolomieu) at a depth of 1-1.5 km, related to the recharge of the superficial reservoir by deeper magma.
– SO2 emissions from the eruptive vent remain low, close to or even below the detection limit. CO2 emissions from the ground in the area close to the volcano are decreasing.
– An outline of the flow could be determined by the OI2 platform (OPGC – Clermont Auvergne University) from the Sentinel 1 satellite data acquired on October 24 (Figure 2). This new contour does not show (or very little) evolution of the flows and their fronts.

Contours of the flows determined from Sentinel satellite data, for the day of October 24, realized by the platform OI2 (University Clermont Auvergne).

– The surface flows could not be estimated today because of lava flows that are too weak at the surface and / or cloud cover.

Chile , Tupungatito :

Special Report on Volcanic Activity (REAV), Metropolitan Region of Santiago, Tupungatito Volcano, October 25, 2018, 23:20 local time (mainland Chile).

The National Geological and Mining Service of Chile (Sernageomin) publishes the following PRELIMINARY information, obtained from monitoring equipment of the National Volcanic Monitoring Network (NVRN), processed and analyzed at the Volcanological Observatory of the Southern Andes (OVDAS) :

Today, Friday, October 26, 2018, at 22:59 local time (01:59 UTC), the monitoring stations installed near the Tupungatito volcano recorded an earthquake associated with a fracturing process of rocks (volcano-tectonic type).

The characteristics of the earthquake, after its analysis, are as follows:

OBSERVATIONS:
At the time of issuing this report, 70 events of similar characteristics of lower magnitude were recorded. The event was not confirmed as felt by the population.
The level of volcanic technical alert remains at the level: Green.

Sernageomin continues online monitoring and will inform in a timely manner about any changes observed.

Volcanic Activity Summary:
Strong seismic tremor from Semisopochnoi consistent with an eruption began at 4:47 UTC (20:47 AKDT) and is currently diminishing. Satellite data through 5:00 UTC (21:00 AKDT) show a small ash cloud at about 12,000 ft asl.
AVO is raising the Aviation Color Code and Alert Level to Orange/Watch for Semisopochnoi.

Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.

An eruptive event was detected in seismic data beginning at 4:47 UTC on October 26 (20:47 AKDT on October 25) and the Aviation Color Code was increased to Orange and the Volcano Alert Level to Watch as a result. This event was characterized by strong volcanic tremor that lasted for about 20 minutes, followed by about 40 minutes of weaker tremor pulses. The event also produced weak infrasound (pressure wave) that was detected by instruments on Adak Island. A thick meteorological cloud deck obscured observations below 10,000 ft asl and a very faint cloud was observed rising briefly above it in a satellite image. It is unclear whether this cloud was related to the eruptive activity or whether it contained any volcanic ash. Seismic tremor ended following this event and seismicity has returned to low levels with occasional earthquake activity. The nature of this eruptive episode is unclear at present and analysis of satellite images in the coming days may provide additional information. This event was not detected by lightning sensors, as would be expected by a large explosion.

Volcanic Activity Summary:
A moderate gas-steam activity of the volcano continues. According to satellite data, a thermal anomaly over the volcano was noted last time on 28 September, 2018, and ash explosions – on 30 September, 2018. The volcano was quiet or obscured by clouds on 01-25 October. KVERT continues to monitor Karymsky volcano.

A moderate gas-steam activity of the volcano continues. The danger of ash explosions up to 13,100-19,700 ft (4-6 km) a.s.l. is remain. Ongoing activity could affect low-flying aircraft.

Costa Rica , Turrialba / Poas / Rincon de la Vieja :

Turrialba Volcano:

Turrialba Volcano Activity Report, 2018-10-26

On 2018-10-26 at 01:34 local time, there is an eruption on the Turrialba volcano, with a column that stood 500 meters above the crater height and 3840 m. (meters above sea level) (12595.2 ft).
Duration of the activity: in progress.
The winds were from the northeast.

Poas Volcano:

No eruptions are reported.
The seismic activity is similar to that of yesterday.
At the time of this report, the winds are blowing west.
The volcano has a degassing activity, the level of seismicity is similar to that of yesterday with Lp type earthquakes and few tremors. The winds move the gas plume westward. No rash or smell of sulfur is reported.

Poas

Rincon de la Vieja volcano:

No eruptions are reported.
The seismic activity is similar to that of yesterday.
At the time of this report, winds are blowing from the northwest.
The volcano has a degassing activity, there is no report of eruption, the winds move the gas to the northwest. The seismicity is similar to that of yesterday with the presence of earthquakes type long periods (Lp).